With rapid development of database technologies, a database storage system presents the following characteristics:
A novel storage device, such as a solid-state drive (Solid-State Drive, SSD) and a phase change memory, and a conventional magnetic disk device constitute a hybrid storage environment. Compared with a conventional magnetic disk, the SSD based on a flash memory has advantages of high performance and low energy consumption, and its price and capacity are between those of a memory and those of the conventional magnetic disk. It is predicted that, in a long time from now, various types of hard disk devices will coexist, and hybrid storage will become a mainstream storage configuration. As there are more and more applications, the data amount of a user grows larger and larger, and an input/output (Input/Output, IO) bottleneck problem caused by conventional data storage is prominent; some important application requirements require a database system to respond quickly, in time, and correctly.
In the prior art, a controller device with a cache is provided between a main memory and an external memory to implement preloading of data of a next request, and transfer the data to the main memory when the request arrives. Alternatively, a flash memory device is used as a level 2 cache; when a buffer of the main memory is full, some data blocks that need to be replaced are written into the flash memory device; and in a startup phase of a database, some hot data is not preloaded according to actual usage of a user.
In the prior art, in an early phase after the database is started, when the amount of data requested by a client is large and a service is very busy, responding efficiency of the database system will be lowered, and IO will be very busy, affecting overall performance of the database system.